Injections of botulism toxin can control an embarrassing condition that makes people sweat so heavily that their clothes get drenched at room temperature, a study found.
The German research adds to the growing list of diverse medical uses for the powerful food-borne poison, which is already used in diluted form to smooth out forehead wrinkles and ease migraine headaches.
"The effectiveness is really hard to believe," said dermatologist Dr. Richard Glogau of the University of California at San Francisco. Glogau said the findings help establish the toxin as the treatment of choice for hyperhidrosis, a sweating disorder that is thought to affect 1 million to 2 million Americans.
Hyperhidrosis, whose cause is unknown, makes people sweat so profusely that they are often humiliated at school or work. Sweaty palms prevent them from shaking hands comfortably, gripping a tool securely or working normally at a keyboard.
"The people who suffer from it are enormously affected," said neurosurgeon Dr. Raj Narayan of Temple University in Philadelphia, who operates on some of these patients. "They also suffer from the fact that nobody else seems to think it's a particularly big deal."
The nerve-paralyzing botulism toxin is one of the most powerful poisons known to medicine and is feared as a potential biological weapon.
In the study published in today's issue of The New England Journal of Medicine, University of Munich doctors injected the diluted toxin into the armpits of 145 patients with hyperhidrosis.
It works by blocking the release of a chemical needed to transmit nerve signals to muscles and sweat glands.
The effect is temporary. Patients slowly began sweating more heavily after two weeks.